Linear regulator with output current and voltage sensing

• US 6,750,638 B1
• Filed: 04/17/2002
• Issued: 06/15/2004
• Est. Priority Date: 04/18/2001
• Status: Active Grant

• Current Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Gang, Elliot Lawrence
• Primary Examiner(s): Riley, Shawn
• Application Number:
  US10/124,963
• Time in Patent Office: 790 Days
• Field of Search: 323/280, 323/281, 323/273, 323/274
• US Class Current: 323/280
• CPC Class Codes: G05F 1/575 characterised by the feedback circuit

Abstract

A linear regulator includes at least two control loops that monitor different control variables of the output signal. The error signal of the first control loop serves as the reference signal for the second control loop. The conversion of one control variable to the other increases phase margin and improves stability of the frequency response. Also, a capacitor can be coupled to the output of the linear regulator to improve small signal and transient response.

Claims

1. A linear regulator for providing a regulated output signal, comprising:

(a) a transresistor that includes an input node, an output node and a control node, wherein the input node is coupleable to a power source;

(b) a control loop circuit coupled to the output node, wherein the control loop circuit monitors a control variable of the regulated output signal and generates an error signal at an error node that is dependent on a difference between a reference signal level and a level of the control variable; and

(c) another control loop circuit coupled to the error node, the output node and the control node, wherein the other control loop circuit is configured to monitor another control variable of the regulated output signal and to generate at the control node a control signal that is dependent on a difference between a level of the error signal and a level of the other control variable, wherein the regulated output signal is dependent on a level of the control signal,

wherein one of the control variable and the other control variable is indicative of one of temperature and pressure.

2. The linear regulator of claim 1, wherein the transresistor comprises a transistor.

3. The linear regulator of claim 1, further comprising an energy storage device coupled to the output node.

4. The linear regulator of claim 3, wherein the energy storage device comprises at least one of a capacitor, inductor, spring, and other storage device of one of mechanical, chemical and electrical energy.

5. The linear regulator of claim 1, wherein the control loop circuit comprises a differential amplifier and a voltage divider.

6. The linear regulator of claim 1, wherein the other control loop circuit comprises another differential amplifier and a voltage-to-current converter.

7. The linear regulator of claim 6, wherein the voltage-to-current converter comprises a current mirror.

8. A linear regulator for providing an output signal, comprising:

(a) means for changing a signal received at an input node responsive to a control signal received at a control node, the changed signal serving as the output signal;

(b) means for generating an error signal at an error node, the error signal being dependent on a difference between a level of a reference signal and a level of a control variable of the output signal; and

(c) means for generating the control signal, the control signal being dependent on a difference between a level of the error signal and a level of another control variable of the output signal,

wherein one of the control variable and the other control variable is indicative of one of temperature and pressure.

9. The linear regulator of claim 8, further comprising means for another control loop circuit that converts voltage to current.

10. The linear regulator of claim 9, wherein the means for converting voltage to current comprises a current mirror.

11. A linear regulator for providing a regulated output signal, comprising:

(a) a mechanical power modulator that includes an input node, an output node and a control node, wherein the input node is coupleable to a power source;

(b) a control loop circuit coupled to the output node, wherein the control loop circuit monitors a control variable of the regulated output signal and generates an error signal at an error node that is dependent on a difference between a reference signal level and a level of the control variable; and

(c) another control loop circuit coupled to the error node, the output node and the control node, wherein the other control loop circuit is configured to monitor another control variable of the regulated output signal and to generate at the control node a control signal that is dependent on a difference between a level of the error signal and a level of the other control variable, wherein the regulated output signal is dependent on a level of the control signal.

12. The linear regulator of claim 11, wherein the mechanical power modulator is a valve.

13. The linear regulator of claim 11, wherein the mechanical power modulator is a temperature controller.

14. The linear regulator of claim 11, further comprising an energy storage device coupled to the output node.

15. The linear regulator of claim 14, wherein the energy storage device comprises at least one of a capacitor, inductor, spring and other storage device of one of mechanical, chemical and electrical energy.

16. The linear regulator of claim 11, wherein one of the control variable and the other control variable is indicative of one of temperature and pressure.